1. Field of the Invention
The present invention relates to an electromagnetic reciprocal drive mechanism such as a linear motor, and in particular to the construction of a movable part thereof.
2. Description of the Related Art
Heretofore, as such an electromagnetic reciprocal drive mechanism there is known one which has for example, a permanent magnet, a support for supporting the permanent magnet, a laminated core provided adjacent to the permanent magnet, and an electromagnetic coil wound around the laminated core. Moreover, the construction is such that an alternating field is formed for example by flowing an alternating current through the electromagnetic coil, and the permanent magnet reciprocates within this alternating field. There is also a mechanism where the permanent magnets are cylindrically arranged to give a permanent magnet cluster. In this case, since permanent magnet pairs repel each other, a woven cloth is wound around the outer periphery of the permanent magnet cluster and the support. Further, the permanent magnet cluster and the support are reinforced by applying an epoxy resin type adhesive from on top of this woven cloth, and impregnating and solidifying the resin therein. The woven cloth that is wound around the permanent magnet cluster and the support, is cut out at appropriate positions after applying the adhesive.
However, in these electromagnetic reciprocal drive mechanisms, the fabrication operation is difficult because the woven cloth stretches due to the application of adhesive, so that there is the likelihood of wrinkles appearing in the woven cloth, and also the possibility that the woven cloth may slip. In addition, because the woven cloth frays in the application of the adhesive, and in particular, the edge of the woven cloth tends to curl up because of the adhesive, dimensional stability in the radial direction is poor. Moreover, there is a problem in that when polyaramid (Kevlar grade) woven cloth is used to ensure strength, because the permeability of the epoxy resin type adhesive is low, then after applying and impregnating a large amount of adhesive, the excess adhesive must be scraped away. Thus not only is a large amount of adhesive necessary, but also because the polyaramid as well as the epoxy resin are both high strength materials, cutting is difficult. Hence these problems are likely to be factors in increasing the cost of such electromagnetic reciprocal drive mechanisms.
It is the object of the present invention to solve the above problem, and provide an electromagnetic reciprocal drive mechanism having a movable part that is simple to manufacture, dimensionally stable and inexpensive.
The electromagnetic reciprocal drive mechanism of the present invention has; a permanent magnet cluster with plate like permanent magnets cylindrically arranged, a support for concentrically supporting the permanent magnet cluster, a laminated core provided adjacent to the permanent magnet cluster, and an electromagnetic coil wound around the laminated core, wherein a sheet having an adhesive layer on an inner surface and which can be impregnated with an adhesive is wrapped around an outer periphery of the permanent magnet cluster and the support, and the permanent magnet cluster is secured to the support by impregnating an adhesive into the sheet and solidifying.
By constructing the invention in this manner, then by wrapping the sheet that is cut according to pre-measurements so that it cannot overlap when wrapping, around the outer periphery of the support and the cylindrically arranged permanent magnets, the sheet is temporarily fixed to the permanent magnets and the support by the adhesive layer. Moreover, by applying and impregnating a small amount of adhesive into the sheet and solidifying, the outer periphery of the support and the permanent magnet cluster is reinforced by the sheet.
In addition, the electromagnetic reciprocal drive mechanism of this invention, is one where in a first aspect, a material of the sheet is paper.
By constructing the invention in this manner, cutting the sheet is not only easy, but there are no distortions produced at the time of wrapping, and fraying of the fiber does not occur when applying the adhesive.
Moreover, the electromagnetic reciprocal drive mechanism of the present invention, is one where in either one of the first and second aspects, a plurality of small holes are formed in the sheet and adhesive layer.
By constructing the invention in this manner, the applied adhesive directly reaches the support and the permanent magnets from the small holes.